Grasslands of Navarre (Spain), focusing on the Festuco-Brometea: classification, hierarchical expert system and characterisation

Abstract

Aims: To clarify the syntaxonomic position of the grasslands in Navarre, with special focus on the dry grasslands, and to characterise the resulting syntaxonomic units in terms of diagnostic species and ecological conditions. Study area: Navarre (northern Spain). Methods: We sampled 119 plots of 10 m2 following the standardised EDGG methodology and analysed them together with 839 plots of similar size recorded in the 1990. For the classification, we used the modified TWINSPAN algorithm, complemented by the determination of diagnostic species with phi coefficients of association, which led to the creation of an expert system. We conducted these steps in a hierarchical manner for each syntaxonomic rank. We visualised the position of the syntaxa along environmental gradients by means of NMDS. Species richness, and structural and ecological characteristics of the syntaxa were compared by ANOVAs. Results: We could clearly identify five phytosociological classes: Lygeo-Stipetea, Festuco-Brometea, Molinio-Arrhenatheretea, Nardetea strictae, and Elyno-Seslerietea. Within the Festuco-Brometea a xeric and a meso-xeric order could be distinguished, with two alliances each, and eight associations in total: Thymelaeo-Aphyllanthetum, Jurineo-Festucetum, Helianthemo-Koelerietum, Prunello-Plantaginetum, Carduncello-Brachypodietum, Helictotricho-Seslerietum, Calamintho-Seselietum and Carici-Teucrietum.Conclusions: The combination of numerical methods allowed a consistent and more objective classification of grassland types in Navarre than previous approaches. At the association level, we could largely reproduce the units previously described with traditional phytosociological methods. By contrast, at higher syntaxonomic level, our analyses suggest significant modifications. Most importantly, a major part of the units traditionally included in the Festuco-Ononidetea seem to fall within the Festuco-Brometea. We could show that bryophytes and lichens are core elements of these grasslands and particularly the Mediterranean ones of Lygeo-Stipetea, both in terms of biodiversity and of diagnostic species. We conclude that the combination of our different numerical methods is promising for deriving more objective and reproducible delimitations of syntaxa in a hierarchical manner. Taxonomic references: Euro+Med (2006–2021) for vascular plants, Hodges et al. (2020) for bryophytes and The British Lichen Society (2021) for lichens, except for Endocarpon loscosii, Heppia lutosa, Psora saviczii and P. vallesiaca, which follow Nimis and Martellos (2021), and Buellia zoharyi, Fulgensia poeltii, Lichenochora clauzadei and Toninia massata, which follow Llimona et al. (2001). Syntaxonomic reference: Mucina et al. (2016), except for those syntaxa specifically treated here and given with authorities. Abbreviations: ANOVA = analysis of variance; EDGG = Eurasian Dry Grassland Group; NMDS: non-metric multidimensional scaling; TWINSPAN = Two-Way Indicator Species Analysis.

Classification of the high‐rank syntaxa of the Central and Eastern Balkan dry grasslands with a new hierarchical expert system approach

“…Here we follow the idea of a hierarchical expert system ( HES ) with identical criteria across the hierarchical levels as recently suggested by García‐Mijangos et al. (2021) for the grasslands of Navarre, Spain, and by Kącki et al. (2021) for the mesic and wet grasslands of Poland. Most recent studies using the ES approach relied largely on ‘mimicking’ established syntaxa from the literature (e.g.…”

“…that should be addressed in the future. Finally, this article deals with the class, order and alliance levels, while initial trials (not included here) indicate that the approach is also able to divide alliances into well-defined associations (see also García-Mijangos et al, 2021). All other authors contributed data, checked/revised and approved the manuscript.…”

“…Chytrý et al (2020) created a system for habitat types of Europe with three levels, but here the set of criteria at different levels varies. Here we follow the idea of a hierarchical expert system (HES) with identical criteria across the hierarchical levels as recently suggested byGarcía-Mijangos et al (2021) for the grasslands of Navarre, Spain, and byKącki et al (2021) for the mesic and wet grasslands of Poland.…”

Proposal (31) to conserve the name Brachypodietalia pinnati Korneck 1974 as a nomen conservandum with a conserved type

“…Therefore, numerous authors throughout Europe now use Korneck's (1974) name Brachypodietalia pinnati to denote the mesoxeric order of the Festuco-Brometea, often explicitly proposing it as a nomen conservandum, e.g. Dengler (2003Dengler ( , 2004, Dengler et al (2003Dengler et al ( , 2012Dengler et al ( , 2019, Boch and Dengler (2006), Löbel and Dengler (2008), Becker et al (2012), Kuzemko et al (2014), Pedashenko et al (2013), Mucina et al (2016), Willner et al (2019Willner et al ( , 2022, Zolotareva and Korolyuk (2019), García-Mijangos et al (2021), Lysenko et al (2021), Magnes et al (2021) and Vynokurov et al (2021).…”

Grasslands and coastal habitats of Southern Ukraine: First results from the 15th EDGG Field Workshop

“…A series of papers has already been published based on the results of the FWs. Among them, there are regional syntaxonomical surveys (Dengler et al 2012;Pedashenko et al 2013;Kuzemko et al 2014;García-Mijangos et al 2021;Magnes et al 2021) and regional studies of patterns and drivers of plant diversity (Turtureanu et al 2014;Kuzemko et al 2016;Polyakova et al 2016;Dembicz et al 2021b). Additionally, data from the FWs represent a relevant part of the "GrassPlot" database (Dengler et al 2018;Biurrun et al 2019) and have been used for several overarching papers dealing with alpha and beta diversity on the continental scale (Dengler et al 2020a;Biurrun et al 2021;Dembicz et al 2021aDembicz et al , 2021cZhang et al 2021).…”